(1) Field of the Invention
The present invention relates to the establishment of fluid-tight couplings between parts and, particularly, to sealing the joints between facing adjacent ends of conduits or the like. More specifically, this invention is directed to sealing rings and, especially, to compressible metal ring seals for use between parts which are to be braced axially with respect to one another. Accordingly, the general objects of the present invention are to provide novel and improved methods and articles of such character.
(2) Description of the Prior Art
Sealing rings for preventing leakage between facing surfaces which lie opposite to one another, and are axially braced with respect to one another, are well known in the art. Such sealing rings are, for example, widely used between lengths of pipe or the like which are to be joined in series by threaded coupling members, the coupling precluding relative axial movement between adjacent pipes. The characteristics of such sealing rings, i.e., the inner diameter, external diameter, thickness and material, for respective applications are typically found in published specifications such as, for example, DIN standards.
A long standing problem in the art is precipitated by the fact that sealing rings designed for the type of usage briefly described above are customarily relatively thick, the thickness being dictated by the desire to minimize the possibility of the rings becoming off-center as a consequence of slipping into threads or recesses in the coupling mechanism. Any such slippage, of course, will result in a portion of the ring extending into the passage carrying the fluid medium, thereby restricting flow and/or causing unacceptable turbulence. The seal ring thickness previously deemed necessary, however, usually leads to an unfavorable, and therefore undesirable, ratio of the compressed width of the ring to its thickness. This is particularly critical in the case of pipes or similar parts which are to be rotated, i.e., tilted axially, with respect to one another since, in such environments, the annular surfaces to be sealed do not reach a final position in which they are precisely parallel to one another or entirely in registration with one another. The sealing ring, accordingly, has to compensate for such lack of parallelism or registration throughout its entire service life.